Involute form dresser for grinding wheels



Dec. 9, 1947. c. lPETERS INVOLUTE FORM DRESSER FOR GRINDING WHEELS FiledFeb.n 14, 1944 2 Sheets-,Sheet 1 t4/ll mpaug@ (Ittomegs Dec. 9, 1947. C,PETERS 2,432,335

INVOLUTE FORM DRESSER FOR `GRINDING WEELS Filed- Feb. 14, 1944 2Sheets-Sheet 2 l 4 Gttornegs Patented Dec. 9, 1947 UNITED STATES PATENTOFFICE lNvoLU'rE FORM DREssER Fon dmNpINcr WHEELS Carl Peters, Dearborn,Mich.

Application February 14, 1944, Serial No. 522,219

(Cl. 12S-11) 19 Claims. l

The present invention relates to grinding wheel dressers, and moreparticularly, to a dresser for imparting an involute form to theperiphery of the grinding wheel.

The primary object of the invention `is to provide a grinding wheeldresser having the various parts thereof so correlated as to cause thedressing tool to traverse a true involute curve and thereby generate agrinding wheel surface having a corresponding involute peripheralsurface.

Another object of the invention is to provide an involute dresser forgrinding wheels in which the 4dresser may be reversed 'so that bothsides of the wheel adjacent the periphery thereof may be cut to form andgenerate an involute curved surface without requiring extensivemeasurements and compilations with respect to the two positions ofoperation.

Another object of the invention is to provide an involute form dresserfor surfacing the peripheral edge lof grinding wheels in which the`dresser is supported between a pair ,of opposed axially aligned`centers to maintain la true relationship with respect to the grindingwheel. Another object of the invention is to provide an involute formdresser for grinding wheels in which the dresser is supported between apair of `opposed axially aligned centers to maintain a true relationshipwith respect to the grinding wheel.

Another `object of the invention is lto provide an involute form dresser4for grinding wheels in which the dressing tool may be adjusted tovarious positions so as to permit the dressing tool to be used forforming involute curve surfaces for various diameter gears withoutrequiring the alteration of the dressing tool except for a minoradjustment to the cutting tool thereof.

Another object of the invention is to `provide an involute form dresserwhich may be supported between the centers of a grinding machine so rasto position the cutting t-ool directly beneath the periphery of the`grinding wheel, thereby ,aiding Vin maintaining a direct relationshipbetween ,the involute form `dresser and a ixed reference point.

Another object of the invention is to provide an involute form dresserof the above-mentioned character which may be quickly and easilyadjusted so as to enable the involute dresser to be used in dressinggrinding wheels with a large number of involute forms depending upon thediameter of the gear and the required involute tooth form.

Another object .of the invention is to provide Aan involute formdresser'for grinding wheels in which all of the parts are so tted andcorrelated as to provide a dresser which will inscribe an ,involuteforni with a high degree yof accuracy .and precision,

Other .Objects and advantages Will become epparent during the course ofthe following description of the accompanying drawings, wherein:

Figure .l is a .top plan View of the inveluie form dresser illustratingportions thereof broken away to show various vdetails of constructionand the arrangement of parts;

Figure?I is an end elevational View of an involute form dresserillustrating the same in its normal position presented directly beneatha grinding wheel to be' Qrmed;

Figure 3 is .a vertical cross ,sectorial View taken on the zigzag line{1H- 3 of Figure 1 looking in the direction of the arrows and,illustrating the manner in which the dresser is rotated to inscribe aninvolute curve and provide a corresponding contour surface on theperiphery of the 'grinding Wheel: y

Figure 4 is a vertical cross sectional view taken o n the irregular line4-4 in `Figure 2 looking in the direction of the arrows, illustratingthe various Vstructural details of the involute form dresser Vand thearrangement and relation thereof between the centers `of a grindingmachine;

Figure 5 4isa diagrammatic view of the dressing cutter illustrating themanner in which the same is moved along an involute curve to generate acorresponding contour` surface on the periphery of the grinding wheel;

Figure 6` is an enlarged fragmentary side elevational View showing thevarious structural details of the slide supporting brackets; and

Figure is a cross`sectional View taken on the diagonal line A"l---'l inFigure 3'looking in the direction of the arrows and illustrating indetail the pivot connection between the adjustable sine bar and themovablerack member.`

In the drawing, Figures land 4 show a grinding machine having a rigidframe 4, a portion only being shown. Mounted upon the machine frame 4are conventional opposing center supports 5 and 6. The center supports 5and 6 are provided with the usual centers jl and 8 and are shown inFigures `2, f3 and l directly beneath a grinding wheel G. The abovestructure is typical of a grinding machine having center supports forsupporting work or the like and the grinding Wheel G is movablevertically with respect -to said supports so that the 4 grinding Wheelmay be fed toward and away therefrom.

The invention comprises an involute form dresser generally designated bythe reference character I0 and said involute form dresser comprises acasing structure generally indicated as Lat Il for being suppOrtedbetween the centers l and 8 of the Aabove-mentioned grinding machine.The caslngstruture Il comprises aframe section including a front wallplate l2 having angular end portions 1 3 and `UL The end well portion I4is slightly offset as at I5 and said angular end portions I3 and I4 areconnected by a plate section I6 fastened in place at its ends by meansof machine screws or the like as at I1. Projections I8 may be formed onthe free edges of the angular end walls I3 and I4 so as to be receivedin rectangular notches I9 formed in the corners of the plate member I6and thereby prevent relative'sliding movement between the casing sectionand the plate member I6.

Fitted on the center support and center 1 is a collar 29 adapted to beheld in place by a set screw 2| and said collar is provided with a flatsurface 22 under which a support or block as indicated in Figure 4 maybe inserted as at 23, the block 23 being seated upon a rigid portion ofthe machine frame 4 so as to hold the center support and collar 20against rotation and provide a substantially rigid and solid support.The collar 26 is provided with a reduced annular boss 24 for beingreceived in an opening 26 in the plate member I6 and said plate memberis positioned on said annular boss 24 in such a manner as to berotatable thereon about the axis of the centers 'I and 8.

Formed integral with the front wall I2 of the frame section is a tubularextension 26 having a bore 21 adapted to receive a tubular extension 28formed on the collar` 20. In assembling the parts, the tubular extension26 is telescoped over the tubular extension 28 with the tubularextension 26 rotatably mounted on the tubular extension 28 so as tofurther increase the supporting surface for the involute form dresserand maintain the parts in their assembled relation.

Fitted on the tubular extension 28 is the hub portion 29 of a sectorgear 30 and said hub portion is rigidly afxed to the collar 26 by meansof machine screws or the like as at 3 I The heads of the machine screwsare received in countersunk bores 32 so as to provide adequate clearancefor the rotation of the tubular extension 26 on the tubular extension28. Gear teeth 33 are formed on the sector gear 30 and it is to be notedthat the sector gear 30 is held in a rigid position against rotation dueto the fact that the same is bolted to the collar 20.

Slidably mounted relative to the frame section and between the sectorgear 30 and angular end wall I4 is a rack bar 34 having rack rteeth 35adapted to engage and mesh with rthe teeth 33 formed on the peripheralsurface of the sector gear 3U. The back wall 35a, of the rack barslidably engages the inner wall surface of the angular end wall I4 asshown clearly in Figures 1 and 3. Secured to the rack bar 34 along oneside thereof is a supporting plate 31 adapted to be fastened in place bymeans of machine screws or the like 38 with their heads received incountersunk bores 39 in the rack bar 34 to permit free sliding movementof the rack bar against the plate member I6. The opposite ends of themachine screw 38 are received in screw-threaded openings 46 in thesupport plate 31 and said support plate is provided with an offsetextension 4I intermediate its ends so that the free end may bebifurcated as at 42 to provide a pair of spaced arms 43. The arms 43 areprovided with openings 44 in axial alignment for receiving a fulcrum pin45 (Figure '1).

Mounted to oscillate on the fulcrum pin 45 and between the bifurcatedarms 43 is a sine bar 46 having its corner portions`at its opposite endsnotched as at 41 (Figure 3) to receive rounds 48. The rounds 48 are heldin place by machine screws or the like as at 49, the heads of which arereceived in countersunk bores 50 extending through the top wall of thesine bar 46. The upper round 43 directly engages the front edge of thesupporting plate 31 whereas the lower round 46 engages one end of agauge block B tightly wedged and frictionally held between thesupporting plate 31 and said lower round 43 so as to maintain the sinebar in a preset adjusted position. Different-sized sine blocks B may beemployed depending on the predetermined angle desired.

Secured to the sine 4bar 46 and extending along the edge thereof is aslotted plate 5I having a longitudinal slot 52 extending from one end tothe other and said slotted plate is provided with a central bracketportion 53 adapted to be fastened tothe sine bar 46 by means of spacedmachine screws 54 with the heads thereof countersunk in suitable boresas indicated in Figure 7. The slotted plate 5I is placed in slidingcontactual engagement with the front wall I2 of the casing section andone end thereof is received in the offset portion I5 of the end Wall I4so as to permit the sine bar to be tilted to approximately 45 degrees asindicated in Figure 3. The outer surface of the tubular extension 26 isattened as at 55 to further permit the free swinging movement of thesine bar and the full travel of the slotted bar 5I to the limit of itsangular movement.

Formed integral with the front wall I2 of the casing section is a pairof spaced bracket arms 56 and 51 and said bracket arms are connected attheir outer ends by an integrated bar 58. The undersides of the bracketextensions 56 and 51 are cut away as at 60 and 6I t-o accommodate anangled slide bar 62 having its angular portion 63 received between thefront wall I2 of the frame section and the cutaway portion of each ofthe bracket arms 56 and 51. A guide rib 64 is secured to the front wallI2 of the casing section by means of suitable machine screws 65 havingtheir heads received in suitable countersunk bores therein. The guiderib 64 is notched as at 66 to receive the upper edge of the angleportion 63 and hold the same in slidable engagement with the front wallI2 of the casing section. The other end of the angled slide bar 62 isguided between a pair of spaced guide members 61 secured to theundersides of the free ends of the bracket extensions 56 and 51 bymachine screws 66 received in countersunk bores therein (Figure 6) Anadditional guide plate or rib 69 is affixed to the llower portion of thefront wall I2 and is similarly held in place by machine screws 16extending therethrough with their heads received in countersunk bores(Figure 4). The guide rib 69 engages the underside of the angled slidebar 62 so as to hold the same against the guide rib 64 and within thenotch 66.

Formed intermediate the ends of the angled slide bar 62 is a V-notch 1Iand fastened beneath the angled slide bar 62 adjacent said notch is aclamping frame 12 having an opening 13 for receiving the lower end of adressing tool support 'll-l so that the same may be held in clampingengagement with the V-notch 1I by means of a set screw 15 threaded in abore in the clamping frame 'J2 as at 16 with the free end of the setscrew engaging the peripheral surface of the dressing tool support 14.The dressing tool support 14 is tubular and is provided with a centrallongitudinal bore 11 terminating at the end in enlarged bores 18 and 19.Received within the enlargel `here 19 is the shank portion `80 of Ianadapter having a head 8| and extendingthrough said bore 11 is a lockingscrew 82 having its head 83 received in said enlarged bore 18 and itsthreaded portion 84 received in a threaded bore 85 in thelshanlr r8l] ofsaid adapter. The head portion 8| of the adapter is provided with a pairof diametrically disposed projections Sla adapted to be received innotches 88 formedin the upper end of the cutting tool support 14. Theadapter 8l is provided with an offset arm 81 having a transverse borefor receiving a diamond cutting tool 88 which may be held in place by aset screw ,or the like as at 89. The diamond cutting tool B8 is held insaid transverse bore 9i) by the set screw 89 so that the diamond cuttingpoint thereof as at 9i `will project from the oifset arm 81 as shown inFigures 2, 3 and 5. Secured to the angle portion 63 of the slide 82 is apin SZhaving its free end projecting through a slot 94 in the front wallcasing section I2 in direct alignment with the slot 52 formed in theslotted plate 5l. The extreme free end of the pin 92 is received in anopening in a sliding block 95 mounted to move in the slot 52 of theslotted bar 5l from one end thereof to the other. provided with anopening 96 for the reception of said pin 92 so that relative slidingmovement between the slotted bar and casing I will impart slidingmovement to said block 95 and a corresponding sliding movement to theslide 62.

Formed intermediate the ends of the integrated bar 58 is a centeringopening 95a having tapered Walls for receiving the conical ends of thecenter' 8 and said tapered opening 95a is in direct alignment with theaxis of the collar 2i! and tubular extension 28. t will thus be seenthat the frame casing iii may be supported between the centers ,1 and 8of a suitable grinding machine so as to position the involute formdresser beneath the periphery of the grinding wheel.

' n operation it will be assumed that the involute form dresser ispositioned between the centers of the grinding machines 1 and 8 as abovedescribed so that the cutting tool holder 14 will be directly beneaththe grinding wheel G (Figures 2 to 5 incl). With the Wheel G in theposition shown in Figure 4, and the sine bar i8 adjusted in the positionshown in Figure 2, the casing frame section I0 may be rotated about theaxis of the centers 1 and 8 from the position shown in Figure 2 to theposition shown in Figure 3. Upon rotation of the `casing i@ the rack bar3d tracks on the stationary sector gear 38 so as to cause a relativesliding movement between the casing I0 and the sine bar d6. This slidingmovement is translated to the diamond point supporting member y'illthrough the medium of the angled slide` bar t2, pin 92 and slotted bar5i. It is noted that rotation of the casing i8 about the centers 1 and 8in a clockwise direction causes the angled slide bar 62 to be moved tothe left a proportionate distance so lthat the end of the diamondcutting tool 9i will inscribe an involute curve as indicated by thedotted line C in Figures 2 and 3. By moving the casing IE) to and fro onits axis so as to oscillate the casing thereon, the diamond point 9iwill generate an involute curve starting from the base circle of thestationary gear and ending at a point determined by the limited rotationof the casing lil. As thecasing I8 is oscillated back and forth, thegrinding wheel G is moved from the full line position shown in Figure ito the dotted line position so as to feed the grinding Wheel into thediamond point 9| and The slide block 8,5 is

thereby form an involute contour I `on the Aperiphery of the grindingwheel Cr. After one side of the peripheral edge of the grinding `wheelhas thus been dressed, the bolt 82 is loosened so as to permit theoffset arm 81 to be swung about an arc of `18() degrees to position thediamond cutting tool `9i on the other side of the wheel to inscribe theinvolute curve C. When the diamond cutting point `9i is thus reversedand the sine bar 46 similarly `reversed by inserting a gauge block underthe other end thereof, the casing lll may be swung in a counterclockwisedirection so as to form and dress the grinding wheel G with an involutecontour I (Figure 5). When the grinding wheel G has been fed to a pointin alignment with the base circle of the sector gear 30 and one side ofthe peripheral grinding wheel edge has thus been dressed, the grindingwheel is retracted and the .offset arm B1 shiftedso as to position thediamond point 9| on the other side of the wheel whereupon :the wheel isagain fed as above described and the casing I0 oscillated in acounterclockwise direction.

In setting the sine bar to the desired angle it is necessary to takeinto consideration the size of the gear for which the grinding wheel isbeing ma-de or formed with contour surfaces to meet the requirements ofthe gear structure. As an example, let it be assumed that the gear is ofa predetermined diameter which diameter is equal to or smaller than thepitch circle of the stationary Igear 38. By simply dividing the basecircle circumference of the sector gear 30 by the base circlecircumference of the gear being constructed, a fraction will be givenwhich will equal the tangent or rate of change of speed which must beimparted to the diamond cutting point 9| when the casing is oscillatedso as t0 give a prescribed involute `curve. Having thus found thetangent which controls the movement of the diamond point cutting tool9i, the sine thereof may be easily found from a trigonometric table sothat the sine bar 46 may be moved to a position to give the requiredacceleration to the diamond point cutting tool 9| by inserting a gaugeblock B of a `known length between the rounds i3 and the rack gear plate1i. For instance, if the gear being considered has a base circlecircumference equal to the base circle circumference of the sector gear3i), by simple division the quotient 1 will be given which is thetangent of 45 degrees. Hence, it will be necessary to set the sine bar46 at such an angle and to do this it is on,y necessary to select thecorresponding sine from a table of trigonometric functions and insert agauge or sine block B as shown in Figure 3. The opposite end of the sineblock when thesine bar is in this position will have its rounds 138engaging the edge of the rack bar plate 31.

It is to be noted that the tool support 14 may be raised or lowered soas to position the damond cutting tool v9i adistance from the axis ofrotation of the casing I0 equal to the radius of the gear for which thegrinding wheel G is being contoured and it is to be noted that whengears havins a smaller diameter than the base c.rc.e of the sector gear30 are under consideration the diamond point tool supporting member 14may be lowered within a considerable range within the radius of thestationary gear 30.

Actually, the motion imparted to the diamond point cutting tool 9| is aretrograde movement `in Vthe direction opposite to the rotation of thecasing l0, That is, the diamond point cutting tool 9| is fedtangentially to increase the distance between the points of the diamondcutting tool and the axis of rotation of the casing a proportionateamount depending on the -angularity of involute contours I and I havebeen formed on the peripheral side edges of the grinding Wheel.

It is to be understood that the form of the invention herewith shown anddescribed is to be taken as a preferred embodiment of the same and thatvarious changes may be made in the shape, size and arrangement of partswithout departing from the spirit of the invention or the scope of thesubjoined claims.

What I claim is:

1. An involute form dresser comprising support means, a frame membermounted to oscillate about a pivotal point on said support means, astationary toothed member within said frame member aiiixed to saidsupport means, a rack slidably mounted in said frame member in trackingengagement with said toothed member, a slide movably mounted on saidframe member to move radially with respect to the pivotal axis thereofand in a plane perpendicular to the movement of said rack, a cutting anddressing tool support secured to said slide extending perpendicularthereto, and an actuator pivotally mounted on the rack having a slidingconnection with said slide to cause the end of said tool support toinscribe an involute curve upon oscillation of said frame member.

2. An involute form dresser comprising support means, a frame membermounted to oscillate abouta pivotal point on said support means, astationary toothed member within said frame member aixed to said supportmeans, a rack slidably mounted in said frame member in trackingengagement with said toothed member, a slide movably mounted on saidframe member to move radially with respect to the pivotal axis of saidframe and in a plane perpendicular to the movement of said rack, acutting and dressing tool support secured to said slide extendingperpendicular therefrom, an adjustable bar member pivoted to the rackmember, and a slidable connection between the bar member and slide tocause the end of said tool support .to travel along an involute curvewhen said frame member is oscillated about its pivotal axis.

3. An involute form dresser comprising support means, a frame membermounted to oscillate about a pivotal point on said support means, astationary toothed member within said frame member affixed to saidsupport means, a rack slidably mounted in said frame member in trackingengagement with said toothed member, a

Vslide movably mounted on said frame member to move radially withrespect to the pivotal axis of said frame and in a plane perpendicularto the movement of said rack, a cutting and dressing tool supportsecured to said slide, a sine bar piving engagement with said toothedmember, a slide movably mounted on said frame member to move radiallylwith respect to the axis of said frame and in a plane perpendicular tothe movement of said rack, a cutting and dressing tool support securedto said slide, and an actuator pivotally mounted on the rack having asliding connection with said slide to cause the end of said tool supportto inscribe an involute curve, said tool support being provided with adiamond cutting tool adapted to be radially presented to the center lineand peripheral edge of a grinding wheel to cut a surface on both sidesof said center line conforming in cross section to the contour of saidcurve when said frame is oscillated about its pivotal axis.

5. An involute form dresser comprising support means, a frame membermounted to oscillate about a pivotal point on said support means, astationary toothed member wit-hin said frame member affixed to saidsupport means, a rack slidably mounted in said frame member in trackingengagement with said toothed member, a slide movably mounted on saidframe member to move radially with respect to the axis of said frame andin a plane perpendicular to the movement of said rack, a cutting anddressing tool support secured to said slide extending perpendicular tothe slide, and an actuator pivotally mounted on the rack having asliding connection with said slide to cause the end of said tool supportto inscribe an involute curve, said cutting and dressing tool supportbeing adjustable relative to said slide and arranged on the center lineof a grinding wheel for movement on either side thereof upon oscillationof said frame member about its pivotal axis.

6. An involute form dresser comprising support means, a frame membermounted to oicillate about a pivotal axis on said support means, astationary toothed member within said frame member afiixed to saidsupport means, a rack slidably mounted in said frame member in trackingengagement with said toothed member, a slide movably mounted on saidframe member to move radially with respect to said axis in a planeperpendicular to the movement of said rack, a cutting and dressing toolsupport secured to said slide extending perpendicular thereto, and anactuator pivotally mounted on the rack having a sliding connection withsaid slide to cause the end of said tool support to inscribe an involutecurve when said frame is oscillated about its axis, said cutting toolsupport being mounted on the slide to permit the longitudinal adjustmentthereof in a direction perpendicular to the direction of movement ofsaid slide and said slide actuator being provided with a surface forbeing engaged by a gauge block interposed between the actuator and rack.

7. An involute form dresser comprising support means, a frame membermounted to oscillate about a pivotal point on said support means, astationary toothed member within said frame member aixed to said supportmeans, a rack slidably mounted in said frame member in trackingengagement with said toothed member, a slide movably mounted on saidframe member to move in a plane perpendicular to lthe movement of saidrack, a cutting and dressing tool support secured to said slide, and anactuator pivotally mounted on the rack having a sliding connection withsaid slide to cause the end of said tool support to inscribe an involutecurve, said actuator being provided with a surface at each end thereoffor being engaged by a: gaugeblock.'- interposed` between the` rack andsaid actuator.

8. An involute form dresser comprising support. means, a frame' membermounted to. oscillate about' a pivotal point. onsaid support means, aStationary toothed member within said frame member afxed to said supportmeans, a rack slidably mounted' in said framemember in trackingengagement withl said toothed member, a slide movably mounted on said'frame member to move radially with respect to the axis of said' frameand in a plane perpendicular to the movement oi said rack, a cutting anddressing tool support secured to saidr slide and extending perpendicularthereto so as to be arranged for movement on either side of the centerline of a grinding wheel, and an actuator pivotally mounted on the rackhaving a sliding connection with said slide to cause the end of saidtool support to inscribel an involute curve on either side of saidcenter line when said framer is oscillated about its pivot point, saidactuator being offset from said rack to permit adjustment thereof tovarious angles whereby the tool support will be moved at various ratesof speed to inscribe involute arcs of different pitch.

9. An involute form dresser comprising support means, a frame membermounted to oscillate about a pivotal pointA on said support means, astationary toothed member within said frame member aixed tosaid supportmeans, a rack slidably mounted in said frame member in trackingengagement with said toothed member, a slide movably mounted on saidframe member to move in a plane perpendicular to the movement of saidrack, a cutting and dressing tool support secured to said slide, anadjustable bary member pivoted to the rack member, and a slidableconnection between the bar member and slide to cause the end of saidtool support to travel along an involute curve when said frame' memberis osciliated about its pivotal axis, said adjustable bar member beingpivoted between its ends with gauge block engaging members' disposed ateach end thereof for being engaged by a gauge block inserted between therack member and said bar to hold said bar in a predeterminedl position,

10. An involute form dresser4 comprising support means, a irame membermounted to oscillate about a pivotal point on said support mea-ns, astationary toothed member within said frame member afxed to said supportmeans, a rack slidably mounted in said frame member in trackingengagement with said toothed member, al slide movably mounted on saidframe member to move in a plane perpendicular to the movement of saidrack, a cutting and dressing tool support secured to said slide, a sinebar pivoted to the rack member, and a sliding connectiony between theslide and sine bar whereby oscillation of said frame member about itsaxis will cause the end of said tool sup-port to traverse an involutecurve, said sine bar being pivoted to the rack intermediate its ends topermit the insertion of a gauge block between the free ends of the sinebar and said rack whereby said sine bar may beheld in a predeterminedadjusted position.

11. An involute form dresser` adapted to be supported on a grinding.machine having a grinding wheel and opposed spaced support centersdisposed therebeneath, comprising a frame member mounted between saidcenters for oscillation about the axis thereof, a grinding wheeldressing tool mounted on said frame member and disposed for movementalong an involute path on 10 either side oi"A the center line of said`grinding, wheel upon oscillation of said' frame member about its axis,means to.` move said dressing tool over the' peripheral edge of thegrinding wheel to` generate an involute contour thereon, and means' foradjustingv said last-named means to cause said dressing tool totravel ina number of'Y involute arcs of different pitch, said adjusting meanscomprisingA a sine bar which may be adjusted to impart` the desiredratev of travel ofV said dressing tool.

12. An involute form dresser for ai grinding machine having a grindingWheel and opposed spaced support centersl disposed therebeneath, supportmeansA disposed between said centers, a frame mounted on said supportmeans for oscillation about the axis of' said centers, a grinding wheeldressing toolmounted on said frame members presented to the' peripheraledge of the grinding wheel and-arranged for movement along an involutepath onf either side of the center line of said grinding wheel, meansIto move` said dressing tool over the peripheral edge of the grindingwheel on one side of said center line to generate an involute contourthereon, means for adjusting said last-named means to cause saiddressing tool to travel in a numberl of involute arcs of diiierent`pitch, andl means to reverse the position of said grinding wheeldressing tool to a location on the other side of said center linetocause the tool to traverse the other peripheral edge of said grindingwheel and dress an involute contour thereon.

13. An involute form dresser for a grinding machine having a grindingwheel and opposed spaced support centers disposed therebeneath,compris'- ing a tubularv support member mounted on one of said spacedcenters iixed against rotation, a casing frame mounted on said tubularsupportand engaging the other spaced' support center to rotate about thecommon axis of said centers, a toothedv gear member within said frameaxed to said tubular support member, a rack slidably mounted in saidframe in rocking engagement -Y with said toothed member, a slidecarriedv by said frame movable radially with respect to the said axis, agrinding wheel dressing tool' support mounted on the slide and arrangedto position a dressing tool beneath the peripheral edge of the grindingwheel forV movement along an involute pathway on either side of thecenter line of said grinding wheel, a sine bar pivoted to the rack, anda slidable connection between the slide and sine bar to cause saiddressing tool to move over ithe peripheral edge of the grinding wheel oneither side of the center line thereof and inscribe an involute formthereon whenlsaid-` casingl frame is oscillated about its axis.

14s. An involute con-tour dresser for aggrinding machine having a'grinding wheel and opposed spaced support centers disposed therebeneath,comprising a tubular support member mounted on one of said spacedcenters xed against rotation, a casing frame mounted on said tubular'support and engaging the other spaced support center to rotate about thecommon axis of said centers, a toothed gear member within said frameaflixed to said tubular support member, a rack slidably mounted in saidframe in rocking engagement with said toothed member, a slide carried bysaid frame formovement radially with respect to said axis, agrindingwheel dressing tool support mounted on the slide arranged toposition a dressing tool beneath the peripheral edge of the grindingwheel for movement along an involute pathway on either side of thecenter line of said grinding wheel, and a sine bar pivoted to the rackintermediate its ends having aslotfor being engaged bya'projection onsaid slide whereby rocking movement of'said frame in one of its tworotational directions will cause said dressing tool to generate aninvolute curve and dress said grinding wheel with a correspondingcontour on one side of said center line corresponding to thepredetermined position of the dressing tool.

15. An involute form dresser for -grinding wheels, comprising a support,a frame member oscillatable about a pivot point on said support, adressing tool slidably carried by said frame member and arranged on thecenter line of said grinding wheel for movement along an involutepathway on either side of said center line, a sectorshaped membersecured to said support, a movable bar member drivingly engaging saidsectorshaped member, a sine bar pivoted to said bar member, and asliding connection between said sine bar and said dressing tool to causesaid tool to inscribe an involute contour on one side of the center lineof the grinding wheel surface as the frame member is oscillated aboutits pivot point in one Vof its two directions of rotational movement andto move said dressing' tool to inscribe an inn volute contour on theother side of said center line of the grinding wheel when said framemember is rotated in its other Adirection of rotational movement.

16. An involute form dresser for grinding Wheels, comprising a support,a frame member oscillatableV about a pivot point on said support, adressing tool slidably carried by said frame member and arranged in aposition for movement along an involute pathway on either side of thecenter lineof said grinding wheel, a sector-shaped member secured tosaid support, a movable bar member kdrivingly Vengaging saidsector-shaped member,a sine bar pivoted to said bar member, and asliding connection between said sine bar and said dressing tool to causesaid toolto inscribe an involute contour on one side of the center lineof the grinding wheel surface as the frame-member is rotated about itspivot point in one of its two directions' ofrotation and to inscribe aninvolute contour on the other side of the center line of the grindingwheel when said frame member is rotated in its other direction ofrotational movement, said sliding connection being adjustable to imparta movement to said tool proportionate to the amount of rotation impartedto the frame member to accommodate involute forms of various pitch. i

17. An involute form dresser for grinding wheels, comprising a support,a frame member oscillatable about a pivot point on said support, adressing tool support slidably carried by said frame member and arrangedfor movement along an involute pathway on either side of the centerlineof said grinding wheel, a sector-shaped member secured to said support,a movable bar member drivingly engaging said sector-shaped member, agrinding wheel surface dressing tool reversibly positioned on saidsupport movable to oppositesides of said center line, and a slidingconnection between said bar member and said dressing tool to cause saidtool to inscribe an involute contouren both sides of thegcenterline ofsaid grinding Wheel surface when the dressing tool is shifted from oneside thereof to the other and as the frame member is oscillated aboutits pivot point, said sliding connection comprising a ysine bar pivotedtothe bar member capable of adjustment to various angles to impart atangential movement to the dressing tool proportionate to the amount ofrotation of the frame member whereby grinding wheels with involute formsof Various pitch may be dressed and said dressing tool being adjustableradially with respect to the pivot point of said frame member to permitthe dressing of involute surfaces generated from various base circles. Y

18. An involute form dresser for grinding wheels, comprising a support,a'frame member oscillatab-le about a pivot point on said support, adressing tool slidably carried by said frame member and arranged formovement along in involute pathway on either side of the center line ofsaid grinding wheel, a sector-shaped member secured to said support, amovable bar member drivingly engaging said sector-shaped member, a sinebar pivoted to said bar member, a sliding connection between said sinebar and said dressing tool to cause said tool to inscribe an involutecontour on one side of the centerline of the grinding wheel surface asthe frame member is rotated about its pivot point in one direction ofrotation and to Cause said dressing tool to' inscribe an involutecontour on the other side of said centerline when said frame member isrotated in its other direction of rotational movement, and a keepermember adapted to engage said support to hold said sector-shaped memberagainst rotary movement when the frame member is oscillated about saidpivot point.

19. An involute form dresser for grinding wheels, comprising a support,a frame member oscillatable about a pivot point on said support, adressing tool slidably carried by said frame member and presentedradially to the peripheral edge of said grinding Wheel for movementalong an involute pathway on opposite sides of the center line of saidgrinding wheel, a sector-shaped member secured to said support, amovable bar member drivingly'engaging said sector-shaped member, a sineb-ar pivoted to said bar members, and a sliding connection between saidsine bar and said dressing tool to cause said tool to inscribe aninvolute contour on a grinding wheel surface as the frame member isoscillated about its pivot point, said depressing tool being reversibleto positions'on opposite sides of the centerline of said grinding wheelto permit the dressing of either side of said grinding wheel adjacentthe peripheral edge thereof.

CARL PETERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,148,955 Molly Feb,v 28, 19392,237,975 Wainwright Apr, 8, 1941 FOREIGN PATENTS Number Country Date621,506 France May 12, 1927 842,033 France June 5, 1939 253,089 GreatBritain 1926

